Zofran (ondansetron) is a medication commonly prescribed to prevent and treat nausea and vomiting caused by chemotherapy, radiation therapy, and surgery.
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Providers on Klarity Health are independent practitioners with clinical autonomy; a diagnosis, treatment, or prescription is not guaranteed.
Providers on Klarity Health are independent practitioners with clinical autonomy; a diagnosis, treatment, or prescription is not guaranteed.
Your provider will discuss treatment options with you, which may or may not include medication.
Zofran is an anti-nausea medication, also known as an antiemetic. It is primarily used for chemotherapy-induced nausea and vomiting (CINV), radiation-induced nausea and vomiting (RINV), and postoperative nausea and vomiting (PONV).
Zofran is no longer available in the United States, but it’s generic, ondansetron is still widely available. The U.S. Food and Drug Administration (FDA) approved Zofran in 1991 for the prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy and repeat courses of moderately emetogenic cancer chemotherapy in patients 6 months and older. Ondanestron was FDA-approved in 1997 for adults and children aged 4 years and older. Off-label, Zofran is sometimes prescribed for morning sickness in pregnancy, motion sickness, vomiting associated with gastroenteritis, and nausea related to migraines.
Ondansetron comes in multiple forms, including oral tablets, orally disintegrating tablets, and an intravenous (IV) form. Ondansetron oral tablets and disintegrating tablets usually start working within 1 to 2 hours of the first dose.
Zofran is a selective serotonin 5-HT3 receptor antagonist, which blocks serotonin’s action in the intestines (gut) and the brain. When serotonin binds to the 5-HT3 receptor, it can trigger nausea and vomiting, especially when the body is exposed to specific substances, like anesthesia or chemotherapy drugs. By blocking serotonin from binding to the receptor, Zofran reduces the signals that trigger nausea and vomiting.
Zofran does not prevent vomiting caused by motion sickness, but it is highly effective for nausea caused by chemotherapy, radiation, and surgery. In a 2018 study, 72.2% of patients undergoing chemotherapy who received ondansetron did not experience nausea and vomiting during the acute phase.
Zofran is FDA-approved for adults and children as young as 6 months old for chemotherapy-induced nausea and vomiting. Ondansetron is FDA-approved for adults and children as young as 4 years of age who are receiving moderately emetogenic chemotherapy treatment.
Zofran is FDA-approved for postoperative nausea in patients aged one month and older. Off-label, it is sometimes prescribed for pregnancy-related nausea or nausea caused by gastroenteritis.
You can get an ondansetron prescription online through a licensed provider after they assess your symptoms.
Board-certified providers licensed to prescribe Zofran include nurse practitioners (NPs), physician assistants (PAs), and doctors (MDs). They can evaluate your symptoms and determine if Zofran is right for you. If Zofran is determined to be medically necessary, your provider can call in your prescription to any online or local pharmacy where you can pick it up or have it delivered to your house.
You can discuss nausea treatment, including medication like Zofran, with a caring, board-certified, licensed provider on Klarity Health.
Ondansetron is available as a disintegrating oral tablet, a film-coated tablet, or an injection solution. Film-coated tablets are available in 4-milligram or 8-milligram doses, and disintegrating oral tablets are available in 4, 8, or 16-milligram doses. The injection solution is available as a 2 2-millimeter single dose or 20-milliliter multiple dose vial.
Zofran dosages for adults
Indication | Film-coated tablet | Orally disintegrating tablet (ODT) |
Highly Emetogenic Chemotherapy | 24 mg (single dose) taken 30 minutes before treatment | 24 mg (three 8-mg tablets) taken 30 minutes before treatment |
Moderately Emetogenic Chemotherapy | 8 mg taken 30 minutes before chemotherapy, followed by another 8 mg dose 8 hours later. Then 8 mg twice daily (every 12 hours) for 1–2 days after treatment | Same as film-coated tablets (interchangeable) |
Radiotherapy | 8 mg taken 1–2 hours before each treatment session, then 8 mg every 8 hours for 1–2 days after treatment | 8 mg three times daily (starting 30 min before treatment, then every 8 hours) |
Postoperative (Before Surgery) | 16 mg taken 1 hour before anesthesia | Same as film-coated tablets (interchangeable) |
Zofran dosages for children
Indication | Age group | Film-coated tablet | Orally disintegrating tablet (ODT) |
Moderately Emetogenic Chemotherapy | 12–17 years | 8 mg taken 30 minutes before chemotherapy, followed by another 8 mg dose 8 hours later. Then 8 mg twice daily for 1–2 days after treatment | Same as film-coated tablets (interchangeable) |
4–11 years | 4 mg taken 30 minutes before chemotherapy, followed by 4 mg doses at 4 and 8 hours after the first dose. Then, 4 mg three times daily for 1–2 days after treatment | Same as film-coated tablets (interchangeable) |
Zofran dosages for injection (IV Use) – Adults & Children (6 months and older)
Indication | Dosage |
Prevention of Chemotherapy-Induced Nausea/Vomiting | 0.15 mg/kg per dose, infused over 15 minutes (max 16 mg per dose). Given 30 minutes before chemotherapy, with additional doses at 4 and 8 hours after the first dose |
Prevention of Postoperative Nausea/Vomiting | 4 mg IV before anesthesia (for adults and children 1 month and older) |
Film-coated ondansetron tablets should be swallowed whole with a small amount of water. Disintegrating tablets should be placed in the mouth and allowed to dissolve before swallowing with saliva. No additional liquid is required.
You may not experience side effects from ondansetron, but if you do, typical side effects can include headache, constipation, fatigue, and diarrhea. Rare but serious side effects can include angina, irregular heartbeat (QT prolongation), hypotension (low blood pressure, severe allergic reactions, grand mal seizures, extrapyramidal reactions (tremors), hypokalemia (low potassium), elevated liver enzymes (AST and ALT), in rare cases, liver failure.
Ondansetron can interact with certain medications, including serotonergic drugs such as SSRIs and SNRIs, and drugs affecting cytochrome P-450 enzymes such as phenytoin, carbamazepine, rifampin, and tramadol.
Ondansetron may not be recommended for individuals with a history of heart disease, irregular heartbeat, liver disease, or low levels of potassium in the blood.
If you take any form of ondansetron and have any side effects, work with your provider and consider reporting negative side effects to the FDA by visiting MedWatch or calling 1-800-FDA-1088.
According to Drugs.com, with its discount, ondansetron costs:
Oral Tablet
• 4 milligrams: $20.59
• 8 milligrams: $16.32
Oral Tablet, Disintegrating
• 4 milligrams: $21.25
• 8 milligrams: $15.92
• 16 milligrams: $998.16
Injectable Solution
• 2 milligrams/milliliters: $11.38
With or without insurance, prescription or drug discount cards from SingleCareRx, drugs.com, GoodRx, WellRx, NeedyMeds, and others can help you save as much as 80% on your prescription.
Zofran (ondansetron) is one of the most effective medications for preventing nausea and vomiting, especially during chemotherapy, radiation, and post-surgery recovery. But it is less effective for nausea associated with motion sickness.
Compazine (prochlorperazine) is an FDA-approved treatment for nausea that works by blocking dopamine receptors in the brain. It is often prescribed for nausea caused by migraines or vertigo. However, it can cause drowsiness, dizziness, and, in rare cases, movement disorders like tardive dyskinesia with long-term use.
Reglan (metoclopramide) helps with nausea by promoting gastric emptying, making it especially useful for individuals with gastroparesis or slow stomach emptying. While it can have fewer side effects than other nausea medications, it carries a risk of movement disorders, including tardive dyskinesia, particularly with prolonged use. Short-term use is recommended to reduce this risk.
Phenergan (promethazine) is another anti-nausea medication that blocks histamine and dopamine to reduce feelings of nausea and vomiting. It is particularly effective for motion sickness and nausea caused by vertigo or post-surgery recovery. However, it is highly sedating, which can be problematic for some. It may also cause dizziness, dry mouth, or low blood pressure.
Each of these medications is FDA-approved for specific uses. Zofran is approved for chemotherapy-induced, radiation-induced, and postoperative nausea and vomiting. Compazine is approved for severe nausea and vomiting and the treatment of schizophrenia. Reglan is approved for nausea, vomiting, and gastroparesis. Phenergan is approved for nausea, motion sickness, and allergic reactions. All have some side effects, including drowsiness, dizziness, and movement disorders.
Talk to a healthcare specialist to find out which anti-nausea medication, Zofran or another antiemetic, is best for you.
Reviews from real patients who received treatment from healthcare providers on Klarity Health.
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*Appointments are generally available within 24 hours. Free initial consultations are available only with select providers. Prescriptions, particularly for controlled substances, may require an in-person evaluation depending on the state of residence and current federal regulations.
The information provided in this article is for educational purposes only and should not be construed as medical advice. Controlled substances may not be appropriate for all patients and any mention of these medications is for educational purposes only, not for marketing or encouraging self-diagnosis. Always seek the guidance of a qualified healthcare professional with any questions or concerns you have regarding your health. Providers on Klarity Health are independent practitioners with clinical autonomy. Nothing in this article is intended to diagnose or treat any condition, including guaranteeing prescription medication of any kind or dosage. Not all providers on Klarity Health prescribe all medications, particularly medications that are controlled substances.
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